1. Field of the Invention
The present invention relates to fuel injectors, and more particularly fuel injectors having coated components.
2. Description of the Related Art
Conventional fuel injectors include metallic components that are attached such that they move jointly within the fuel injectors. For example, during manufacture of some air assist fuel injectors, a poppet of a first material is press fit into a receiving portion of an armature of a second material. During this press fitting process, the poppet and armatures are often galled such that air pockets form between the surface of the armature and the surface of the poppet. After the poppet is press fit to the armature, they are typically welded together. During operation of the fuel injector, the armature and the poppet move in a reciprocating linear motion within the fuel injector. Although the poppet and the armature typically do not move with respect to one another, the base material of the poppet and armature occasionally corrodes near or at the poppet-armature interface where the poppet is attached to the armature. The dissimilar materials, the air pockets, and the weld connection are thought to contribute to galvanic corrosion, crevice corrosion, and intergranular corrosion at the poppet-armature interface of these conventional fuel injectors. Additionally, the poppet-armature interface is thought to be susceptible to stress corrosion cracking as these components are often subjected to tensile stresses and corrosive environments.